1. Field of the Invention
The present invention relates to a device for the regulation of the fuel-air mixture of an internal combustion engine.
2. Description of the Prior Art
It is a known practice to regulate the air-fuel mixture of an internal combustion engine by acting on one or more of the parameters determining this mixture using the information from a probe arranged in the exhaust pipe which supplies the regulation device with an electric signal which is variable as a function of the composition of the gases burned.
In French Pat. Nos. 73.23453, 74.18029, 74.32606 it is disclosed that this regulation may also be modulated as a function of the amount of air passing through the carburettor by means of a capsule having a membrane or the equivalent which is subject to the reduced pressure prevailing at the venturi neck situated in the control device.
Internal combustion engines can be fed with various fuels and in particular gaseous fuel. In the case of liquid fuel, the regulation can be applied to the flow of liquid fuel supplied by a carburettor or the equivalent or to the air flow (oxidant) or alternatively to a secondary air flow as described in the above French Patents. In the case of gaseous fuel, substantial differences of structure appear. The carburettor or equivalent is in fact eliminated and the regulation is applied to an inflow of gas which directly provides a regulation of power by the variation of the quantity of gas admitted, whereas the liquid fuel devices must function close to stoichiometry.